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Foulacy
Bronze Member
USA
65 Posts |
 Posted - 12/22/2008 : 04:08:45
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I have a ph-1 phaser and it makes a strange thump when engaged AND disengaged. It's not a pop, it's more of a thump. I did read the thread about a "Plop" noise on an OD-1. It could very well be the same problem. I opened it and did not notice anything strange. All joints look original on the pcb. I can post pics if needed although I have a feeling it's the switch, but maybe not? I also have a ph-1r and opened it to compare but their boards were definitely different. So the question is, what is the thump? Is it "normal" (dont think so right lol)? Any ideas?
Also, I noticed a trim-pot on both models and I'm guessing it's for depth. Am I right?
Thanks everyone. |
Edited by - Foulacy on 12/22/2008 04:15:50 |
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Dr. Bob
Moderator
Australia
6593 Posts |
Posted - 12/22/2008 : 15:14:23
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Hi Foulacy
Has it always done that?
And can you tell us anything else about what might have happened to it?
Please post some pics, it always helps the Tech Guys.
Regards Dr. Bob
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Foulacy
Bronze Member
USA
65 Posts |
Posted - 12/23/2008 : 11:24:09
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It has always done this since I've owned it. The sound only occurs when turning it on and off. Effect is normal, buffering is normal. When in front of the amp it is faint on the clean channel and loud with gain on (although you can't hear it if you're playing and switch it off). In an effects loop it is the same volume clean or distorted. I've tried it on two different amps in two different houses through different guitars. Plus, all my other pedals all function the same. I have tried the standard old school ACA adapter, daisy chaining a PSA style adapter and a battery. All with the same result.
here are pics: http://s4.photobucket.com/albums/y105/Foulacy/PH-1%20PCB/
I tried to take pics of the board with two different cameras and I seriously could not get a picture in focus. I guess that's a problem with cheaper digital cameras since they don't even HAVE a manual focus.
Reading the thread about MullyFX's OD-1, Laurie mentioned the D9 was flipped around the wrong way. I for one can not find the D9 on this board, but I wonder if it's the same problem. I don't know what the D9 does but perhaps the corresponding capacitor on this board is also flipped around? |
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Laurie
Double Platinum Member
Canada
4854 Posts |
Posted - 12/23/2008 : 15:56:56
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Hi Foulacy!
May I respectfully ask... does your camera have a "macro" mode? (my Canon has a little button with a flower beside it) Engaging macro, if you have it, will clean up the pics.
The diode numbers change from pedal to pedal. I turns out I don't have a PH-1 schematic(!), so when I get my hands on one I'll let you know the diode (and cap) numbers. |
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Laurie
Double Platinum Member
Canada
4854 Posts |
Posted - 12/23/2008 : 16:31:00
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My thanks to Christo for the schem!
The diode to check is D6... make sure it is around the right way - the side witht he stripe should be connected to C18. |
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Foulacy
Bronze Member
USA
65 Posts |
Posted - 12/24/2008 : 04:18:53
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| Ok I am looking at the pcb and am not seeing c18. Should the stripe be facing the bottom of the board or the rest of the board? Bottom meaning, the bottom edge (like if you were facing it from above) not the actual underneath. |
Edited by - Foulacy on 12/24/2008 04:30:19 |
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Dr. Bob
Moderator
Australia
6593 Posts |
Posted - 12/24/2008 : 04:35:27
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Hi Laurie, Christo & Guys
I have the Sch. but does anyone have the actual service notes?
Regards Dr. Bob |
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Laurie
Double Platinum Member
Canada
4854 Posts |
Posted - 12/24/2008 : 04:49:54
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Foulacy
Bronze Member
USA
65 Posts |
Posted - 12/24/2008 : 04:56:18
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so I assume that means the stripe would be closer to the bottom edge of the board than to the top?
here's D6 circled:
as you can blurrily see, the yellow stripe on D6 is closest to the bottom edge of the board. correct or no? |
Edited by - Foulacy on 12/24/2008 05:02:23 |
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Laurie
Double Platinum Member
Canada
4854 Posts |
Posted - 12/24/2008 : 05:15:32
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Correct.
Switrching noise almost has to be in the switching ciruit (kinda obvious i guess!) - so the first thing I'd do is swap D6 and C18 for new ones. If C18 has failed, it will thump for sure.
How comfortable are you with a soldering iron?
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Edited by - Laurie on 12/24/2008 05:20:27 |
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Foulacy
Bronze Member
USA
65 Posts |
Posted - 12/24/2008 : 05:23:52
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pretty darn comfortable I've soldered my share of pickups. never soldered on a pcb board though. what are the values of D6 and C18?
Also, I'm not sure if this is common to all PH-1's, but it distorts right in the middle of the sweep with most hard picking when placed in front of the amp, even with just a single coil pickup. In the effects loop, 0 distorting. Would this also have anything to do with C18 or D6? |
Edited by - Foulacy on 12/24/2008 05:24:55 |
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Laurie
Double Platinum Member
Canada
4854 Posts |
Posted - 12/24/2008 : 05:35:46
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C18 and D6 won't affect the sound like you describe (I believe..). It might be the bias adjustment producing the sound you describe.
Anyway... I'd try swapping C18 for a new one as a first step.
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Edited by - Laurie on 12/24/2008 05:36:30 |
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Foulacy
Bronze Member
USA
65 Posts |
Posted - 12/24/2008 : 05:44:56
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| ok what value is D6? I assume my electronics store would have both of these? |
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Laurie
Double Platinum Member
Canada
4854 Posts |
Posted - 12/24/2008 : 05:55:02
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| 1N4148, or any small signal silicone diode will do the job. |
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Topic |
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PH-1 Problem
